1. Field of the Invention
This invention relates to the conversion of carbon monoxide, hydrogen and alcohol containing mixtures with a new class of heterogeneous catalyst having exceptional chemical and thermal stability, high upper reaction temperature limits, and good catalytic activity for conversion of organic compounds, said catalyst comprising a substrate which is modified by at least one amine functional member coordinated to a metal function, said amine functional member acting as a bridging member between said substrate and said metal function.
2. Description of Prior Art
There has long been a need for effective, commercially practicable transition metal catalysts for such reactions as hydrogenation, hydroformylation, carbonylation, dimerization and others. Early catalysts developed for such purposes were homogeneous catalysts which suffered from, among other things, the expense of recovering, repurifying and recycling said catalysts. Changes in selectivity and reactivity were often brought about by varying ligands and by changes in operating conditions, such as, for example, temperature, pressure, reactant ratios, reaction rates and others. Catalyst losses were often so high that relatively inexpensive metals such as cobalt were used, even though such catalysts required severe operating conditions. Catalysts which were effective under somewhat milder conditions, such as rhodium complexes, were much more expensive (of the order of 10.sup.3 times as expensive), and, therefore, to insure low catalyst loss, created the requirement of costly recovery systems.
More recently, a number of heterogeneous catalysts have been developed (Belgium Pat. No. 721686) which demonstrate activities and selectivities for certain reactions, such as, for example, hydroformylation. Those heterogeneous catalysts are comprised of transition metal complexes on ligands bonded to macroporous resins and show superior catalytic results in certain reactions, such as hydroformylation, when compared to their homogeneous analogues. However, the utility of said heterogeneous catalysts is limited by the relatively low chemical and thermal stability of the resin supports therein.
Another class of heterogeneous catalyst has been developed comprising complexed transition metals on phosphine ligands bonded to inorganic oxide surfaces (Dutch Pat. No. 7,018,453 and British Pat. No. 1,275,733). This class of catalysts has been shown to be useful in the hydroformylation reaction (Dutch Patent No. 7,018,322).
U.S. Pat. Nos. 3,941,819; 2,496,265; 2,579,828 and 2,588,511 and Australian Pat. No. 126,007 teach conventional catalysts and supports for use in Fischer-Tropsch synthesis reactions. For example, U.S. Pat. No. 2,579,828 discloses a catalyst comprising a metal or metal oxide which may be supported on a clay, silica gel or alumina for use in a multi-step process for converting CO and hydrogen to hydrocarbons; U.S. Pat. No. 2,496,265 shows the use of a metal impregnated silica gel as a catalyst; U.S. Pat. No. 2,588,511 teaches the use of a catalyst comprised of "reduced ground fused mixture of iron oxide and a mixed silicate of aluminum and a metal selected from the group consisting of the alkali and alkaline earth metals".
The instant invention of conversion of carbon monoxide and hydrogen containing mixtures, with a new class of heterogeneous catalyst, which catalyst comprises a substrate having a minimum surface area of about 10 m.sup.2 /g and having pores with a minimum pore diameter of about 5 Angstrom Units, said substrate being modified by at least one amine functional member coordinated to a metal function, said amine functional member acting as a bridging member between said substrate and said metal function, is demonstrated to provide benefits unmatched by use of prior resin-bound heterogeneous catalysts or oxide-bound phosphine functionalized heterogeneous catalysts. The catalyst for use in this invention has enhanced organic compound conversion activity, e.g. Fischer-Tropsch synthesis activity, relative to other oxide-bound or resin-bound complexes. With respect to catalytic activity, the catalyst for use herein shows dual-functional catalytic activity, e.g. in which an olefin is hydroformylated to an aldehyde which is then converted by an acid functionality of the catalyst to an acetal in the presence of an alcohol.
Further, the catalyst for use herein does not convert to catalysts of the prior art during use, i.e. it does not decompose or otherwise change to the catalytic materials of the art when subjected to carbon monoxide-hydrogen conversion conditions identified hereinafter.